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vmmcache: initial implementation

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Matheus
2024-05-24 18:03:24 -03:00
parent 7673a365e8
commit 48b7fb4324
21 changed files with 772 additions and 134 deletions
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kernel-src/mm/vmm.c
+54 -17
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@@ -6,6 +6,7 @@
#include <limine.h>
#include <string.h>
#include <kernel/slab.h>
#include <kernel/vmmcache.h>
#define RANGE_TOP(x) (void *)((uintptr_t)x->start + x->size)
@@ -217,9 +218,18 @@ static void destroyrange(vmmrange_t *range, uintmax_t _offset, size_t size, int
proc_t *proc = thread ? thread->proc : NULL;
cred_t *cred = proc ? &proc->cred : NULL;
if ((range->flags & VMM_FLAGS_FILE) && (range->flags & VMM_FLAGS_SHARED)) {
__assert(VOP_MUNMAP(range->vnode, vaddr, range->offset + offset, mmuflagstovnodeflags(range->mmuflags) | (range->flags & VMM_FLAGS_SHARED ? V_FFLAGS_SHARED : 0), cred) == 0);
if ((range->flags & VMM_FLAGS_FILE) && ((range->flags & VMM_FLAGS_SHARED) || range->vnode->type == V_TYPE_CHDEV)) {
// shared file mapping or character device mapping
if (range->vnode->type == V_TYPE_CHDEV) {
// character device mapping
__assert(VOP_MUNMAP(range->vnode, vaddr, range->offset + offset, mmuflagstovnodeflags(range->mmuflags) | (range->flags & VMM_FLAGS_SHARED ? V_FFLAGS_SHARED : 0), cred) == 0);
} else if (arch_mmu_iswritable(_cpu()->vmmctx->pagetable, vaddr) == false || arch_mmu_isdirty(_cpu()->vmmctx->pagetable, vaddr) == false) {
// dirty page cache mapping
vmmcache_makedirty(pmm_getpage(physical));
pmm_release(physical);
}
} else {
// anonymous or private non character device mapping
pmm_release(physical);
arch_mmu_unmap(_cpu()->vmmctx->pagetable, vaddr);
}
@@ -289,6 +299,15 @@ static void unmap(vmmspace_t *space, void *address, size_t size) {
}
static void printspace(vmmspace_t *space) {
printf("vmm: ranges:\n");
vmmrange_t *range = space->ranges;
while (range) {
printf("vmm: address %p size %lx flags %x\n", range->start, range->size, range->flags);
range = range->next;
}
}
static void *zeropage;
bool vmm_pagefault(void *addr, bool user, int actions) {
@@ -335,8 +354,28 @@ bool vmm_pagefault(void *addr, bool user, int actions) {
// page not present in the page tables
if (range->flags & VMM_FLAGS_FILE) {
uintmax_t mapoffset = (uintptr_t)addr - (uintptr_t)range->start;
__assert(VOP_MMAP(range->vnode, addr, range->offset + mapoffset, mmuflagstovnodeflags(range->mmuflags) | (range->flags & VMM_FLAGS_SHARED ? V_FFLAGS_SHARED : 0), cred) == 0);
status = true;
if (range->vnode->type != V_TYPE_BLKDEV && range->vnode->type != V_TYPE_REGULAR) {
// map non cacheable vnodes
__assert(VOP_MMAP(range->vnode, addr, range->offset + mapoffset, mmuflagstovnodeflags(range->mmuflags) | (range->flags & VMM_FLAGS_SHARED ? V_FFLAGS_SHARED : 0), cred) == 0);
status = true;
} else {
// cacheable vnode
page_t *res = NULL;
int error = vmmcache_getpage(range->vnode, range->offset + mapoffset, &res);
if (error == ENXIO) {
// TODO if error returned == ENXIO, raise an urgent SIGBUS on the calling thread
__assert(!"TODO: sigbus");
} else if (error) {
printf("vmm: error on vmmcache_getpage(): %d\n", error);
status = false;
} else {
status = arch_mmu_map(_cpu()->vmmctx->pagetable, pmm_getpageaddress(res), addr, range->mmuflags & ~ARCH_MMU_FLAGS_WRITE);
if (!status) {
printf("vmm: out of memory to map file into address space\n");
pmm_release(pmm_getpageaddress(res));
}
}
}
} else {
// anonymous memory. map the zero'd page
status = arch_mmu_map(_cpu()->vmmctx->pagetable, zeropage, addr, range->mmuflags & ~ARCH_MMU_FLAGS_WRITE);
@@ -346,12 +385,16 @@ bool vmm_pagefault(void *addr, bool user, int actions) {
pmm_hold(zeropage);
}
}
} else if (arch_mmu_iswritable(_cpu()->vmmctx->pagetable, addr) == false){
} else if (arch_mmu_iswritable(_cpu()->vmmctx->pagetable, addr) == false) {
// page present but not writeable in the page tables
void *oldphys = arch_mmu_getphysical(_cpu()->vmmctx->pagetable, addr);
if ((range->flags & VMM_FLAGS_FILE) && (range->flags & VMM_FLAGS_SHARED)) {
// TODO shared file mappings (set as dirty and set as writable on PTE)
arch_mmu_remap(_cpu()->vmmctx->pagetable, oldphys, addr, range->mmuflags);
if (range->vnode->type != V_TYPE_CHDEV)
vmmcache_makedirty(pmm_getpage(oldphys));
status = true;
} else {
void *oldphys = arch_mmu_getphysical(_cpu()->vmmctx->pagetable, addr);
// do copy on write
void *newphys = pmm_allocpage(PMM_SECTION_DEFAULT);
if (newphys == NULL) {
@@ -360,7 +403,9 @@ bool vmm_pagefault(void *addr, bool user, int actions) {
} else {
memcpy(MAKE_HHDM(newphys), MAKE_HHDM(oldphys), PAGE_SIZE);
arch_mmu_remap(_cpu()->vmmctx->pagetable, newphys, addr, range->mmuflags);
pmm_release(oldphys);
if ((range->flags & VMM_FLAGS_FILE) == 0 || range->vnode->type != V_TYPE_CHDEV)
pmm_release(oldphys);
status = true;
}
}
@@ -429,6 +474,7 @@ void *vmm_map(void *addr, volatile size_t size, int flags, mmuflags_t mmuflags,
if (flags & VMM_FLAGS_FILE) {
// XXX make sure that writes can't happen to executable memory mapped files and check file permissions
vmmfiledesc_t *desc = private;
__assert((desc->offset % PAGE_SIZE) == 0);
range->vnode = desc->node;
range->offset = desc->offset;
VOP_HOLD(desc->node);
@@ -602,15 +648,6 @@ void vmm_switchcontext(vmmcontext_t *ctx) {
arch_mmu_switch(ctx->pagetable);
}
static void printspace(vmmspace_t *space) {
printf("vmm: ranges:\n");
vmmrange_t *range = space->ranges;
while (range) {
printf("vmm: address %p size %lx flags %x\n", range->start, range->size, range->flags);
range = range->next;
}
}
extern void *_text_start;
extern void *_data_start;
extern void *_rodata_start;